2.4. Connecting to an Ethernet 802.1q VLAN

Virtual LANs are a way to take a single switch and subdivide it into
logical media segments. A single switch port in a VLAN-capable switch
can carry packets from multiple virtual LANs and linux can understand
the format of these Ethernet frames. For more on this, see
the linux
802.1q VLAN implementation site.

Kernels in the late 2.4 series have support for VLAN incorporated into
the stock release. The vconfig tool, however needs
to be compiled against the kernel source in order to provide userland
configurability of the kernel support for VLANs.

There are a few items of note which may prevent quick adoption of VLAN
support under linux. Ben McKeegan wrote a
good
summary of the MTU/MRU issues involved with VLANs and 10/100
Ethernet. Gigabit Ethernet drivers are not hamstrung with this problem.
Consider using gigabit Ethernet cards from the outset to avoid these
potential problems.